printfn "%s" (encrypt ("HXUCZVAMDSLKPEFJRIGTWOBNYQ".ToCharArray()) ("PTLNBQDEOYSFAVZKGJRIHWXUMC".ToCharArray()) ("WELLDONEISBETTERTHANWELLSAID".ToCharArray()))
printfn "%s" (decrypt ("HXUCZVAMDSLKPEFJRIGTWOBNYQ".ToCharArray()) ("PTLNBQDEOYSFAVZKGJRIHWXUMC".ToCharArray()) ("OAHQHCNYNXTSZJRRHJBYHQKSOUJY".ToCharArray()))